A possible link between a deadly form of stroke and smoking has been discovered by scientists.
Researchers in Finland found a sharp drop in the number of people who suffered a subarachnoid haemorrhage - the most fatal form of stroke - occurred in the same period as a decline in smoking numbers.
Between 1998 and 2012, the number of people who smoked plunged 30% among 15 to 64-year-olds in the country, the study found.
During this time, cases of the killer stroke also went down by 45% among women under 50 and 38% among men under 50, as well as by 16% among women over 50 and 26% among men over 50.
Scientists said they could not establish whether the change in smoking habits caused the drop, but it was "highly likely" Finnish tobacco policies played a role.
A British charity said the findings were a "wake-up call" to smokers.
In recent years, Finland has slashed smoking numbers through a series of public health campaigns and legislative action against the sale of tobacco and its use in public.
Professor Jaakko Kaprio of the University of Helsinki said of the findings, which were published in the journal Neurology: "It is extraordinary for the incidence of any cardiovascular disease to decrease so rapidly at the population level in such a short time.
"Even though we cannot demonstrate a direct causation in nation-wide studies, it is highly likely that the national tobacco policies in Finland have contributed to the decline in the incidence of this type of severe brain haemorrhage."
Health charity Ash said the findings should motivate smokers in the UK to quit.
Chief executive Deborah Arnott said: "The Finnish study is a wake-up call to smokers.
"They need to know that if they don't quit smoking they're twice as likely to die from stroke than non-smokers.
"But stopping smoking can be tough, which is why it is so important to ensure that all smokers are given the best possible support and encouragement to give up."